Belt conveyor for transporting tobacco materials

ABSTRACT

An apparatus for transporting loose tobacco material includes a transporting belt, equipped with a vibratory sub-assembly with independent driving elements and a feeding channel placed over the transporting belt. The vibratory sub-assembly has the form of at least two separate vibratory portions, each having at least one roller with eccentric elements and symmetrically arranged counterweights. Each of the vibratory portions has separate adjusting elements to provide independent adjustment of the magnitude and direction of vibration amplitude vector, and also has separate adjusting elements providing independent adjustment of the frequency of the transporting belt vibrations, independently of speed of the transporting belt. An additional belt conveyor having vibratory portions is mounted over the transporting belt.

FIELD OF THE INVENTION

The invention relates to a belt conveyor for transporting tobaccomaterials.

BACKGROUND OF THE INVENTION

Flat belt conveyor with one vibratory portion (a roller) is known fromU.S. Pat. No. 5,641,055, the vibratory portion serving to distribute thetransported material uniformly across the transporting belt of theconveyor (along its width). The vibratory portion has a separate,independent drive. The vibratory roller is symmetrically, drum-likeshaped, narrowing towards its ends, thereby the maximum amplitude ofdeflection is achieved in the middle of the transporting belt anddecreases from the center towards both walls. Speed of the belt issynchronized with rotational speed, i.e., frequency of strikes againstthe belt so as to avoid multiple striking against the same portion ofthe transported material. Such a conveyor does not meet a function ofcompacting.

From U.S. Pat. No. 4,703,846 a trough belt conveyor is known, in whichside rolls positioned at an angle relative to the horizontal directionare formed so as to cause vibrations of the transported material throughthe transporting belt, additionally to decreasing friction against theside walls of the conveyor as a result of rolling friction, such thatparticles of the material agglomerate in a created trough makingimpossible or minimizing relative mechanical interaction betweenimmobile parties. This conveyor does not meet a function of compactingeither.

From U.S. Pat. No. 4,911,827 a flat belt conveyor for cleaninggrain/seed is known with a vibratory portion.

BRIEF DESCRIPTION OF THE INVENTION

The purpose of the invention is to provide a belt conveyor fortransportation of an organic material such as plants, herbs andparticularly tobacco on a transporting belt, being fed continuously anduniformly across all the width of the transporting belt at its feedingportion with simultaneous compaction of the material duringtransportation, i.e., increasing density of the transported materialbetween the feeding point under a feeding channel and a discharge pointfrom the conveyor.

The belt conveyor according to the invention illustratively fortransporting loose tobacco material, has a transporting belt equippedwith a vibratory sub-assembly with a separate driving device and afeeding channel placed over the belt, with the vibratory sub-assembly ofthe transporting belt having a form of at least two separate vibratoryportions, each of them having at least one roller provided witheccentric elements and symmetrically arranged counterweights, and incase of using eccentric elements of the same active radii on the rollersof all the vibratory portions, the distance between the transportingbelt and axes of the rollers of the starting vibratory portion in whichfeeding of the comminuted tobacco material takes place, is minimal, thedistance from the transporting belt to axes of the rollers of successivevibratory portions is an increasing function, and when axes of therollers of all the vibratory portions are at the same distance from thetransporting belt then the active radius of the eccentric elements ofthe starting vibratory portion is the largest and the radius decreasesfor the eccentric elements of the rollers of successive vibratoryportions, and ech of the vibratory portions has separate adjustingelements providing independent adjustment of magnitude and direction ofthe vibration amplitude vector, and has also separate adjusting elementsproviding independent adjustment of frequency of the transporting beltvibrations, irrespective of speed of the transporting belt.

Each vibratory portion is preferably equipped with separate adjustingelements providing adjustment of a distance and inclination of eachvibratory portion relative to the transporting belt, rollers of each ofthe vibratory portions being connected through belt pulleys withseparate driving arrangements, separate relative to the driving assemblydriving the transporting belt, the driving arrangements of vibratoryportions are equipped with adjusting elements providing adjustment ofrotational speed of motors being part of these driving arrangements.

Preferably, an additional belt conveyor having vibratory portions ismounted over the transporting belt.

Preferably, a pressure plate having vibratory portions is swinginglymounted over the transporting belt.

Preferably, a stationary or rotary scraper bucket is mounted over thetransporting belt, and includes adjusting elements for adjusting theheight of the scraper bucket relative to the transporting belt surfaceand adjusting the scraping bucket position relative to the transportingbelt surface along the horizontal axis extending along the direction ofthe transporting belt movement.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are presented with reference toaccompanying drawings, in which:

FIG. 1 is a side view of a belt conveyor according to the invention,

FIG. 2 is a perspective view of a belt conveyor according to theinvention,

FIG. 3 shows a single vibratory portion of the belt conveyor accordingto the invention,

FIG. 4 is a side view of three successive vibratory portions of the beltconveyor according to the invention,

FIG. 5 illustrates a second embodiment of the belt conveyor according tothe invention, comprising an additional belt conveyor with vibratoryportions, and

FIG. 6 shows a third embodiment of the belt conveyor according to theinvention, comprising a scraper bucket.

FIG. 7 shows an example of a swingingly mounted pressure plate.

DETAILED DESCRIPTION OF THE INVENTION

A belt conveyor according to the invention illustratively shown in FIG.1 compacting comminuted/loose tobacco material has tension roller 2placed in a tensioning portion T1, and a driving roller 1 placed in adriving portion D1 with a mounted thereto external drive (not shown), aload-bearing structure in form of a vibratory sub-assembly, and atransporting belt 3, transporting a material fed in portion A. Thesurface of the transporting belt may be smooth or may be profiled,depending on technological requirements.

The vibratory sub-assembly has the form of three separate vibratoryportions V1, V2, V3, each of them having three rollers 10A equipped witheccentric elements 10B and symmetrically arranged counterweights 10C. Inthe case of using identical eccentric elements 10B on rollers 10A of allvibratory portions V1, V2, V3, the distance between the transportingbelt 3 and the axis of the rollers 10A of the first vibration portionV1, corresponding to a starting portion, in which feeding of the loosetobacco material takes place, is minimal. The distances from thetransporting belt 3 to the axes of rollers 10A of the successivevibratory portions V2, V3 are increasing functions, and when axes ofrollers 10A of all vibratory portions V1, V2, V3 are at the samedistance from the transporting belt 3 then the active radius ofeccentric elements 10B of the first vibratory portion V1 is biggest andthe radius decreases for eccentric elements 10B of rollers 10A ofsuccessive vibratory portions V2, V3.

Each of the vibratory portions V1, V2, V3 has separate adjustingelements formed by rollers 10A and providing independent adjustment ofintensity and direction of a vector of the vibration amplitude, and hasalso separate adjusting elements formed by eccentric elements 10B andproviding independent adjustment of frequency of the transporting belt 3oscillations, irrespective of the belt transporting rate.

The adjusting elements adjust the distance and, optionally, inclinationof each vibratory portion V1, V2, V3 relative to transporting belt 3,while rollers 10 a of each vibratory portion V1, V2, V3 are connectedthrough pulleys 11 with separate driving arrangements, the drivingarrangements being separate relative to the driving arrangement whichdrives the transporting belt 3, driving arrangements (not shown) of thevibratory portions V1, V2, V3 are equipped with adjusting elementsadjusting rotation rate of motors forming part of these drivingarrangements.

The distances between the driving rollers 10A of a vibratory portion canbe independently adjusted so that amplitude of pre-selected, desiredvalue is applied where necessary to maximize impact force transmittedfrom each roller's eccentrics 10B through the transporting belt 3 to thestream of tobacco 6. Independently of that, revolutions of the rollers10A within each of the vibratory portions V1, V2, V3 are adjusted bysetting revolutions of the driving motor and/or transmission ratio toeach vibratory portion. In this way, the frequency of the roller'srotation is adjusted. By having the mutually independent means ofsetting positions where both amplitude and frequency are transmittedfrom the rollers through the transmission belt 3 to the conveyedproduct. e.g., loose tobacco, specifically advantageous acceleration canbe applied to the stream of the conveyed product to orient looseparticles of the conveyed product and thus compact the productefficiently and uniformly.

An additional belt conveyor 12 is fastened to the side walls 5 over thetransporting belt 3, the belt conveyor 12 comprising vibratory portionsas shown in FIG. 5 or a pressure plate 14 (FIG. 7) comprising vibratoryportions is mounted swingingly on pins protruding from the side walls 5over the transporting belt 3.

As shown in FIG. 6, a stationary or rotary scraper bucket 13 may beattached to the side walls 5 over the ending portion of the transportingbelt 3, the scraper bucket 13 being equipped with adjusting elements foradjusting the height of the scraper bucket 13 relative to the surface ofthe transporting belt 3 and for adjusting the position of the scraperbucket 13 along the horizontal axis X extending along the movementdirection of the transporting belt 3.

As mentioned above, the conveyor according to the invention may have aplurality of mechanical vibratory portions V1 . . . Vn. In an exemplaryembodiment shown in FIG. 2 there are only three vibratory portions V1,V2, V3 placed under the upper surface of the transporting belt 3, whichgenerate transversely directed vibrations, preferably perpendicularly tothe direction of the belt movement (transport). According to theinvention, characteristic feature of the conveyor is that both amplitudeas well as frequency of vibrations of each vibratory portion are chosen,adjusted, and controlled irrespective of motion parameters of thetransporting belt 3, including its linear speed.

Rotation of eccentric rollers 10 a in each vibratory portion V1, V2, V3is synchronized via pulleys 11 with a toothed belt, not shown in thedrawing. It means that the rotation of the rollers 10 a, the rotationgenerating an amplitude of vibrations, is synchronized in each portionand may be controlled for example by a separate driving arrangement witha separate motor, irrespectively of motion parameters of thetransporting belt 3. Such a solution allows for full control ofvibratory movement of each roller 10 a and in each of the vibratoryportions V1, V2, V3 irrespectively of controlling all motion parametersof the transporting belt 3.

The upper profile of the transporting belt 3 may be chosen and adjustedaccording to the technological process requirements by suitableregulation and/or applying some elements generating vibrations ofrequired profile. For zero amplitude of the vibrations the upper surfaceof the transporting belt 3 may be inclined at a slight angle relative tothe horizontal direction, however it may be positioned horizontally, asin the presented solution.

Side walls 5 are placed on both sides of the belt conveyor shown in FIG.1, the side walls profiling stream of the transported material andprecluding spillage of the material outside the conveyor. FIG. 2presents how the side walls 5 are positioned relative to the beltconveyor. In the proposed solution shown in FIG. 2, the profiling sidewalls 5 are fastened to the supporting frame 9 a–9 e by means ofbrackets 5 a.

The belt conveyor according to the invention has a various, optimal fora given process, number of vibratory portions V1 . . . Vn and and/or anumber of kinds thereof, the vibratory portions generating vibrations ofthe transporting belt 3. Three identical vibratory portions V1, V2, V3occur in the presented embodiment, as shown in FIG. 2. FIG. 3 shows aview of a single module of a vibratory portion. In the presentedsolution supporting frame 9 a–9 e of the vibratory sub-assemblycomprising vibratory portions form supporting side plates 9 c withtransverse stiffeners 7, 8 which serve also as supports for movingtransporting belt 3. In order to reduce motion resistance of thetransporting belt 3, low-friction liners 4 c are attached to the uppersurfaces of the stiffeners 7, 8. Because of operational reasons, thelow-friction liners applied in the tensioning portion T1 and the drivingportion D1 have form of plates 4 a and 4 b, as shown in FIG. 1.

Rollers 10 a are installed in the supporting frame 9 a–9 e, eccentricelements 10 b and symmetrically arranged counterweights 10 c beingassembled with the rollers 10 a, the eccentric elements generatingdesired vibrations of the transporting belt 3. Mounting the rollers 10 ain bearings arranged in the supporting frame 9 a–9 e allows them torotate as a result of which vibrations of the transporting belt 3 aregenerated, the belt being tossed up by rotating eccentric elements 10 b.Position of each vibratory portion V1, V2, and V3 relatively to thetransporting belt 3 is adjusted by means of adjusting elements such thatdirection and magnitude of a vector of maximal vibration amplitude canbe set according to a decreasing function, optimal for a given process.Thus a position of any vibratory portion V1, V2, and V3 may be changedalong the axis X-Y-Z (FIG. 1) and, moreover, each of the vibratoryportions V1, V2, V3 may be inclined at an angle relative to thetransporting belt 3.

All the vibratory portions have separate driving means. In the proposedsolution choosing and controlling of amplitude and frequency ofvibration along the transporting belt 3 is achieved, irrespective ofspeed of the given transporting belt 3. Preferably, each vibratoryportion V1, V2, V3 has its own, separate driving arrangement. It is alsopossible that the transporting belt 3 as well as individual vibratoryportions V1, V2, and V3 are driven by a single motor throughtransmission gear arrangements.

Moreover, amplitude and frequency of vibrations in each of the vibratoryportions V1, V2, V3 may be adjusted and controlled within a given range,irrespective of values set in other portions. According to the inventionthe amplitude of vibrations of the transporting belt 3 of the conveyoris biggest in the starting portion of the conveyor, in which feeding ofthe material takes place, and is a characteristic function for a givenprocess, and decreases in successive portions, i.e., amplitude of thefirst vibratory portion V1 is maximal whereas amplitude of the lastvibratory portion V3 is minimal for a given series of vibratoryportions, this being a result of employing the smallest distance betweenthe first vibratory portion V1 and the transporting belt 3 and thelongest distance between the third vibratory portion V3 and thetransporting belt 3 when identical eccentric elements 10 b are used orelse employing a maximal active radius of eccentric elements 10 b in thefirst vibratory portion V1 and a minimal active radius of eccentricelements 10 b in the third vibratory portion V3 when identical distanceof axes of the rollers 10 a of all the vibratory portions V1, V2, V3from the transporting belt 3. Thus a desired compaction of thetransported tobacco is achieved, prior to discharge from the conveyor.

FIG. 4 shows an arrangement of eccentric elements and distribution ofvibration amplitude of the transporting belt 3 surface where the maximalvibration amplitude of the upper surface of the transporting belt 3 isachieved in the portion V1 while the minimal in portion V3.

An additional effect achieved by applying the above mentionedinnovations is advantageous polarization of particles of the transportedtobacco material. The tobacco material particles are chaoticallydistributed in the feeding zone A while in consequence of vibratorytreatment during transportation on the conveyor according to theinvention the particles leave the conveyor in the discharge zone B insuch a manner that they tend to minimize free space therebetween andtake the position, being optimally parallel each to other.

In order to form a predetermined shape of the stream of the transportedmaterial and to avoid spilling out the processed material, side walls 5in form of a forming/sealing channel are placed adjacently along thelength of the transporting belt 3, preferably beyond the transportingbelt 3, as shown in FIG. 1.

The side walls 5 extend from the tension roller 2 at least to thedriving roller 1, with a possibility of extending beyond the tensionroller 2, in order to allow for correct, continuous transfer of theformed and compacted material stream to a successive machine and toavoid any disturbance of the stream of the tobacco particles at thedischarge point.

Furthermore, it is possible to attach above the material beingtransferred on the belt 3 an additional belt conveyor 12 with vibratoryportions, mounted within the side walls 5, as shown in FIG. 5. Thepurpose of this additional upper belt conveyor 12 is to intensify and/orfacilitate compaction of the transported material. The purpose may bealso to intensify and/or facilitate a uniform or any desireddistribution of the transported material across the transporting belt 3.The upper belt conveyor 12 may be replaced by a pressure plate 14 havingvibratory portions arms 14 a swingingly mounted (FIG. 7) on pinsprotruding from the side walls 5 and means of applying additionalpressure 14B. The purpose of the plate 14 is vibratory pressing down thetransported material thereby compacting or facilitating compactionand/or distributing the material transported on the transporting belt 3.

FIG. 7 shows an example of a swingingly mounted pressure plate 14 wherethe plate is hung above the tobacco stream and its suspension point 14Ais positioned and fixed to the conveyor's side walls above thetransporting belt 3. Compressing action of the pressure plate can becontrolled by adjusting an independently controlled force that can beapplied dynamically by e.g. a pneumatic servo-motor 14B and/or adjustingdead-weight of the plate 14.

Furthermore, it has turned out to be advantageous to provide the beltconveyor according to the invention with a stationary or rotary scraperbucket 13, as shown in FIG. 6, placed in the ending portion of thetransporting belt 3. The scraper bucket 13 may be installed on the sidewalls 5, irrespective of the additional belt conveyor 12 or the pressureplate 14. The scraper bucket 13 is equipped with adjusting elements 13A(FIG. 6) for adjusting its height relative to the belt surface and foradjusting its position along the horizontal axis X. Employing thescraper 13 makes it possible to obtain a constant level of thetransported material at the output of the conveyor, irrespectiveof—fluctuations of feeding the material onto the conveyor.

1. A belt conveyor for transporting loose tobacco materials, comprising:a transporting belt, equipped with a vibratory sub-assembly withindependent driving means, a feeding channel placed over thetransporting belt, wherein the vibratory sub-assembly of thetransporting belt (3) comprises at least two separate vibratory portions(V1, V2, V3), each comprising at least one roller (10 a) havingeccentric elements (10 b) and symmetrically arranged counterweights (10c), wherein in case of using eccentric elements (10 b) of the sameactive radii on the rollers (10 a) of all the vibratory portions (V1,V2, V3), the distance between the transporting belt (3) and the axes ofthe rollers (10 a) of the starting vibratory portion in which feeding ofthe loose tobacco material takes place is minimal, and the distance fromthe transporting belt (3) to the axes of the rollers (10 a) ofsuccessive vibratory portions (V2, V3) is an increasing function, andwherein when the axes of the rollers (10 a) of all the vibratoryportions (V1, V2, V3) are at the same distance from the transportingbelt (3) then the active radius of the eccentric elements (10 b) of thestarting vibratory portion (V1) is the largest, and the radius decreasesfor the eccentric elements (10 b) of the rollers (10 a) of successivevibratory portions (V2, V3), and wherein the roller (10 a) of each ofthe vibratory portions (V1, V2, V3) is adjustable to provide independentadjustment of magnitude and direction of a vibration amplitude vector,and the eccentric elements (10 b) provide independent adjustment offrequency of the transporting belt vibrations, irrespective of speed ofthe transporting belt (3).
 2. A belt conveyor according to claim 1wherein each of the vibratory portions (V1, V2, V3) is equipped withseparate adjusting elements providing adjustment of distance andinclination of each of the vibratory portions (V1, V2, V3) relatively tothe transporting belt (3), and the rollers (10 a) of each vibratoryportion (V1, V2, V3) are connected by pulleys (11) with separate drivingarrangements, separate relative to the driving arrangement which drivesthe transporting belt (3), the driving arrangements of the vibratoryportions (V1, V2, V3) are equipped with adjusting elements providingadjustment of rotational speed of motors forming a part of these drivingarrangements.
 3. A belt conveyor according to claim 1 or 2 furthercomprising an additional belt conveyor (12) including vibratory portionsmounted over the transporting belt (3).
 4. A belt conveyor according toclaim 1 or 2 further comprising a pressure plate 14 having vibratoryportions (14A, 14B) mounted swingingly over the transporting belt (3).5. A belt conveyor according to claim 1 or 2 further comprising astationary or rotary scraper bucket (13) mounted over the ending portionof the transporting belt (3), equipped with at least one adjustingelement (13A) providing adjustment of the height of the scraper bucket(13) relative to the surface of the transporting belt (3) and adjustmentof the position of the scraper bucket (13) relative to the surface ofthe transporting belt (3) along the horizontal axis (X) extending alongthe direction of the transporting belt (3) movement.